(1) Technical Field
The subject invention relates to test assemblies for evaluating the form, fit and function of preassembled wiring harnesses and more particularly to test stands including holders and detecting devices for testing completed wiring harnesses for open and shorted circuits and for the presence of clip and clamps on the harness for mounting it in a vehicular environment.
(2) Description of the Prior Art
It is known to provide a test stand for supporting a preassembled wiring harness for vehicular or other use so as to evaluate the form, fit and function of such preassembled harnesses. The need for such pretesting of modern day wiring harnesses is self-evident when considering the complexity of the electrical systems of automobiles and the like. In the past evaluation of such wiring harness has included use of a dedicated test stand having a solid plywood face on which connector holders and other presence detecting devices are mounted. Typically, such dedicated test stands have a single faceplate which is in the order of two feet high by four to ten feet long depending upon the length of the wiring harness being tested.
In such known test stands the single plywood face plate has specified holes cut therein to receive the holders and presence detecting devices which interface with the mounting brackets and terminals of a given preassembled harness design. Since each model of preassembled wiring harness has a different layout, each test stand is specially configured for one wiring harness. A large number of test stands of special design can require extensive storage facilities. Also, small changes in a design of a given wiring harness configuration can require extensive rework of the specially designed single plywood face plate.
Such rework can include cutting new holes and puttying or otherwise filling prior holes in the original faceplate layout. Changes can occur in wiring harness designs during the course of a model year. Such changes require that special test stands be taken off the plant floor and reworked at a separate location to accommodate running changes in the wiring harness design during the model year.
In specially designed test stand designs, the holders and presence detecting devices once mounted on such plywood faceplates are wired to either standard interface circuit boards or special test circuit boards located inside a test stand enclosure. Such holders and detection devices have discrete separate wires with crimped on sleeve terminals at each end which respectively connect each holder test pin with a single male pins on the interface circuit board. Such wires have variable lengths to accommodate the different special layouts on the faceplate and also require adhesive strip flags to label each end of wire to assure proper connection of the holder or detector device and the interface circuit board.
Such test stands have an electronic harness tester mounted on top of an enclosure. The enclosure has a single plywood faceplate with a length designed to accommodate the single wiring harness model to be tested thereon. The electronic harness tester is located at fixed connection points on such enclosures. It is mounted by drilling special holes in the bottom of the tester housing. Screws are directed through such holes to secure the tester housing on the top of the enclosure. Other mounting arrangements for the tester can include use of a mounting bracket system with arms which compress the tester housing between upper and lower clamp arms or alternatively the housing can be held in place on the enclosure by metal straps. In all cases, the harness tester housing is connected and disconnected by use of tools and held in a special relationship (fixed) with respect to interface circuit boards within the enclosure.
The wiring harness has test harness end connectors joined to test sockets in the holders. The holders are connected to either the standard interface circuit boards or to circuit boards specifically designed for each kind of special test sequence. The harness tester is operative to select and to record or indicate the tested function. A large number of different length wires run through a single compartment enclosure. A large single access door is on the rear of the enclosure. The door closes the complete length of the enclosure at its back. The door is held in place by elaborate latch and hinge elements. A ribbon cable for connecting the harness tester to the interface circuit boards passes between the top of the rear access door and the edge of the rear door at a pinch point.
The interface boards in prior test stands are connected to the harness tester by ribbon cables at a male pin, female connector matrix on the board. A 64 pin connector connects to the harness tester while the matrix of individual male pins is the point of connection for the specially designed array of discrete, individual holder and detector wires which run from each pin of holders on the faceplate to each male pin of interface circuit boards so as to serve as either electrical or presence "coupling" means in the assembly.
In order to special test wiring harness functions such as the resistance of the resistance wiring in the harness, relay testing, bulb burn and other special wiring harness functions, special circuit boards designed for such tests are provided. In the past, the special circuit boards and regular interface boards were mounted into a common extrusion. However, to interface such special boards with the harness end connectors has required splicing into the discrete wires from the standard interface boards to the test holders.
Other stand type systems include U.S. Pat. No. 3,653,411 which discloses a single compartment enclosure having a front face onto which wiring components are joined to form an assembly. The faceplate constitutes a pegboard into which nails are pressed to define routing for wire. There is no suggestion of a system for solving the problem of how to quickly change the holder positions in a test system for checking electrical functions and mounting features of a wiring harness which is preassembled at one point and then moved to the test stand where terminals on the wiring harness are connected to holders on the test stand. Further the '411 patent does not disclose a modular type test stand which can be shortened or lengthened to support different sized wiring harness which can be joined by cables of a fixed standard length(s) to operatively connect circuit board and harness tester units of a system for functionally testing the operation of such preassembled varieties of wiring harness.
U.S. Pat. No. 3,705,374 (Tuller) discloses a support box on which wire components are assembled. The system includes a light indicator sequenced to instruct an assembler which wire to pick from a component supply during the course of the wiring assembly. Special connectors interface the light indicator and the faceplate of the assembly stand. As in the case of the aforementioned '411 patent, the Tuller proposal requires that each assembly setup have a fixed location for the connectors thereon. If a new harness is placed on the front face the faceplate must be reworked by drilling new holes and filling of old holes. There is no suggestion of use of modular standard length test stand components which can be aligned to accommodate different length, preassembled wiring harnesses or which can be configured to enable holders to be connected to interface boards by the use of standard length cables.
U.S. Pat. No. 4,183,091 discloses a wiring board for assembling wire components from a storage case. The board includes a plurality of LED lamps which are wired through the board to indicate proper routing of the wire components during an assembly process wherein the wire components are routed by guide pins. U.S. Pat. No. 4,483,373 discloses still another version of a wire assembly stand. The '091 and '373 patents do not disclose an arrangement for mounting holder components on a faceplate in a manner which will enable them to be fastened to conform to a first preassembled wiring harness configuration and which will further enable the holders to be readily repositioned to accommodate a variant of the wiring harness configuration. There is no provision to electrically test a preassembled harness and there are no modular units located end to end to accept different length wiring harness designs while enabling the interface boards and harness testers to be connected by standard length cables. Further, there are no holders which have a test socket on one end adapted to mate with an end connector on a wiring harness and wherein the test socket is prewired to a standard length cable having an end connector which fits through faceplate slots for access to mating connector pins on an interface circuit board.
While the prior art discussed above accomplishes the purposes set-forth therein, they are unable to meet the need for quick turn around of a wiring harness test stand for testing the form, fit and function of wiring harnesses for use on a wide range of vehicle types and especially for quick turn around of a specific wiring harness design which is slightly modified during the course of a model year change.